1. Field of the Invention
This invention relates to a reclining chair, particularly an office swivel chair, comprising a frame, a seat carrier, and a backrest carrier having an adjustable inclination, which carriers are connected to the frame for performing a synchronous movement relative to the frame, wherein the backrest carrier at its bottom end extends under the seat carrier and is connected to the seat carrier by at least one connecting element for moving simultaneously with the seat carrier. The arrangement is such that a person sitting on the chair is adapted to perform a movement by which the backrest carrier is moved from a steep position to a reclined position and by said movement the backrest carrier is lowered and the seat carrier is moved forwardly at the same time and at least the rear portion of the seat carrier is lowered.
2. Description of the Prior Art
Published German Application 39 30 983 discloses such a chair in which a synchronous movement can be performed, by which the seat carrier is moved forwardly and its rear portion is lowered and the backrest carrier is reclined. That movement is imparted to the chair by synchronizing levers, which involve a complicated mechanism. Besides, the backrest carrier and the seat carrier are interconnected by pivot means so that the two parts cannot be moved independently of each other. Whereas the provision of the synchronizing levers, which are pivoted at a plurality of points, has the result that the relative movement of the backrest and the seat, which movement promotes the shirt-stripping effect, is substantially reduced, that relative movement cannot entirely be eliminated because the two carriers are directly interconnected.
In accordance with Published German Application 26 42 091 the bottom end of a backrest carrier is guided by an arcuate track, which extends below the seat. The track may be constituted by sleeves or by guiding rollers, which roll in corresponding slots. The backrest carrier is moved about an imaginary axis, which extends through the hip joints of the user. But because the seat carrier cannot be displaced forwardly so that the center of gravity of the user cannot be displaced, the backrest can be reclined only to a limited extent. Besides, during the reclining movement it is inconvenient that the seat carrier is not lowered at least in its rear portion because the shirt-stripping effect will thus be promoted, which is due to the raising of the backrest carrier relative to the back of the user.
EP 0 303 720 discloses a reclining chair in which an L-shaped backrest carrier is moved along two guides from a steep position to a reclined position. During that movement the top end of the backrest carrier is lowered and, at the same time, the seat carrier, which is directly connected to the backrest carrier by a pivot, is moved forwardly and its rear portion is slightly lowered. But the forward portion of the guide for the backrest carrier is so designed that the forward portion of the seat carrier is undesirably raised during the reclining movement. Because the backrest carrier is L-shaped, it is guided during its reclining movement by two guides. Whereas said guides still permit a movement about an imaginary axis, the large radius determined by the guides requires that axis to be substantially stationary and to be disposed on the chest or belly level in front of the user at a small distance from him. The backrest carrier and the seat carrier cannot move independently of each other because they have a common pivotal axis.
Published European Patent Application 36 824 and WO 87/06810 disclose reclining chairs in which a relative movement about an imaginary axis through the hip joints of the user is imparted to the seat and the backrest. Said chairs are not designed to permit a displacement of the center of gravity and it is difficult to guide the backrest carrier relative to the seat carrier along an arc because this might result in an overcenter movement of the backrest carrier. For this reason, adjusting mechanisms are provided, by which the movement of the backrest carrier is restrained.